Heterocyclic polymers from triaminopyradine compounds

ABSTRACT

Thermally stable polymers are obtained by cyclodehydration of the precyclized prepolymers which are produced by reaction of acid derivatives such as bis(acid halides), mono(acid halide)anhydrides and dianhydrides, with specific triaminopyridine compounds.

[451 July 22, 1975 Gerber HETEROCYCLIC POLYMERS FROM [56] ReferencesCited TRIAMINOPYRADINE COMPOUNDS UNITED STATES PATENTS Inventor: ArthurGerber. University 3.740.140 6/1973 Gerber 260/295 Heights. Ohio3,804,804 4/l974 Gerber et a] 260/47 [73] Assignee: HorizonsIncorporated, Cleveland.

Ohio Primary ExammerLester L. Lee

Attorney, Agent, or Firm-Lawrence I Field [22] Filed: Mar. 4, I974 [2|]Appl. No.2 447,639 {57] ABSTRACT Thermally stable polymers are obtainedby cyclodehy- (52] U.S. Cl 260/47 CP; 260/30.2; 260/306 R; dration ofthe precyclized prepolymers which are pro- 260/308 R; 260/30.8 DS;260/32.6 N; duced by reaction of acid derivatives such as bis( acid260/49; 260/65; 260/78 TF halides). mono(acid halide)anhydrides anddianhy- [5 l] Int. Cl C08g 20/32 drides, with specific triaminopyridinecompounds. [58] Field of Search 260/47 CP, 65, 78 TF. 49

10 Claims, No Drawings HETEROCYCLIC POLYMERS FROM TRIAMlNOPYRlDINECOMPOUNDS It is well known that aromatic diamines are precursors topolyimides and aromatic tetraamines of the biso-diamine type areprecursors to polybenzimidazoles, polyimidazopyrrolones,polybenzimidazobenzophenanthrolines, and polyquinoxalines, e.g., asdescribed in my recently published paper in Journal of Polymer Science(Polymer Chemistry Edition) 11,1703 (1973). Many of these polymers haveexhibited excellent thermal, chemical, solvent and radiation resistanceand have found utility in a variety of forms, such as films, fibers,laminating and adhesive systems, matrices for structural composites andsemi-permeable membranes. Unfortunately, the bis-o-diamines are oftenextremely sensitive to oxidation, often produce gelled polymer, andtheir use has been severely restricted in commercial applicationsbecause of their high cost.

It has been found that specific triaminoaromatics can be successfullypolymerized with very reactive acid derivatives, including bis(acidhalides), at mild reaction conditions to produce completely gel-freepolymers which have excellent solution stability. These polymers in turncan be cyclodehydrated to thermally stable polymers which show improvedsolubility and/or thermal stability as compared to analogous materialsoutside the scope of this invention. This improved thermal stability isquite unexpected since polyimides derived from bipyridyl diamines[American Chemical Society, Organic Coating and Plastics ChemistryPreprints, 33, No. l, 177 (1973)] and a polybenzimidazole derived fromthe diacid chloride of 2,6-pyridinedicarboxylic acid [Macromolecules, 5,807 (1972)] have been reported to exhibit poorer thermal stability thanthe corresponding benzenoid polymers.

Polymers derived from aromatic triamines and mono(acid halide)anhydrides(derived from tribasic acids) or dianhydrides have been reported inKobunshi Kagaku 24 (267), 50, (1967); J. Macromolecules Science,Chemistry 2 (6) 1275 (1968); J. Polymer Science, Part B 6 (1), 49(1968); Japanese Patent 70/20,l55, and US. Pat. No. 3,532,673. Thesepolymers were either prepared in hot (l40-230C) polyphosphoric acid fromthe triamine or triamine acid salt or by a two-step process whichinvolved condensation of the free triamine in an aprotic solvent withsubsequent cyclodehydration to cyclized polymers. The latter route,unlike the polymerization process of this invention, is extremelysensitive to stoichiometry which if not adhered to strictly, leads togelled polymer, and also affords polymer solutions with limitedstability. Furthermore, it has been reported that conventional triaminessuch as 1,2,4-triaminobenzene and 3,4,4- triaminobiphenyl, or their acidsalts, produce gelled polymer upon reaction with bis( acid halides) inaprotic solvents.

A process for preparing polyimides has been described in US. Pat. No.3,632,554 wherein the diamine may be partially replaced by up to 60 moleof a triamine, a tetraamine, or mixtures thereof. A representativetriamine and tetraamine therein disclosed, are 2,3,6-triaminopyridineand 2,3,5,6-tetraaminopyridine. The patented process unlike the processutilized in the present invention uses free polyamines and not theiracid salts. Furthermore, the amount of diamine replacement in thepatented process is limited. but in the process of the presentinvention, the mole ratios of triamine/diamine or triamine/tetraaminecan vary without any such limit, that is they can vary from 99/1 to l/99or even more broadly.

One object of this invention is to provide cyclized heterocyclicpolymers which are soluble, thermally stable, and which can be easilyconverted into useful intractable materials by virtue of crosslinkingreactions.

Another object of this invention is to provide soluble precyclizedpolymer precursors to the afore-mentioned cyclized polymers, the saidprecyclized polymers exhibiting excellent stability following theirformation.

A further object of this invention is to provide a method utilizing verymild reaction conditions, for the preparation of the above solubleprecyclized polymers.

Still another object of the invention is to produce such polymers frommonocyclic monomers which are relatively inexpensive.

The cyclized heterocyclic polymers of this invention contain at leastone of the following recurring structural units represented by theFormulae 1, ll, [II or IV.

Formula IV in which R is a trivalent radical represented by the formulawherein one bond from either an a or 7 position is bonded to the -NH or=N- group in the above cyclized struc tures [IV; and

wherein each R represents a monovalent member selected from the groupconsisting of hydrogen, methyl, ethyl, propyl, butyl and pentyl, andboth R; members are not required to be the same; and R is a monovalentmember selected from the group consisting of hydrogen, alkyl,substituted alkyl, alkenyl, substituted alkenyl, arylalkyl, substitutedaryalkyl, aryl, substituted aryl, heteroarylalkyl, heteroaryl,substituted heteroaryl, with aryl and heteroaryl including monocyclic,linear bicyclic and fused ring structures, in which typical substituentswithin the scope of this invention include: methyl, phenyl, pyridyl, F(aromatic), Cl (aromatic), CN, COOH and its salts, COOC H SO H and itssalts, SH, thioaryl, thioalkyl, CH=CHC H and N, N,N-(dialkylamino),Suitable R 's include the following which are intended to be merelyillustrative and not exhaustive of suitable groups which may be R ethyl,methyl, propyl, butyl, pentyl, allyl, crotyl, phenyl, biphenyl, pyridyl,quinolyl, N,N-(dialkylamino)-alkyl, -C H COOH and salts thereof, C -H SOH and salts thereof;

+ 2 -)U G 4 -(-CH ),,C H,SH, and

wherein v is 0, 1, or 2.

R R and R are divalent, trivalent, and tetravalent radicalsrespectively, selected from the following structural types: aliphatic,cycloaliphatic, alkenyl, perfluoroalkyl, perfluoropolyalkylene oxide,aromatic and heteroaromatic, and inorganic/organic radicals, thecarbocyclic and heterocyclic radicals having a single, multiple or fusedring structure, the multiple ring struc tures including polyaryleneswith 2 to 9 aryl rings in which the aryl groups are bonded directly toeach other or bridged by a divalent member selected from the groupconsisting of alkylene with up to 3 carbon atoms, perfluoroalkylene of 2to 10 carbon atoms, O,

CH=CH-, 5- and 6-membered heteroaromatics containing at least onenitrogen atom, and mixtures 6 the inorganic/organic radicals consistingof ferrocenyl, carboranyl, and biaryls separated by at least onephosphorus atom or by at least one silanyl or siloxanyl group, andmixtures thereof; R represents H, lower alkyl, or phenyl.

The polymers represented by Formulae I-lV are preferably prepared fromthe linear precyclized polyamides, V, VI, and VII, and acid saltsthereof, by a cyclodehydration reaction.

C 0 H and wherein each of R R R R and R has the meanings previouslygiven to it in Formulas I-IV.

The cyclodehydration of precyclized polymers V-VII to polymers I-lV isaccomplished by known methods including heating under vacuum or inertatomsphere; in tetramethylene sulfone or diphenyl sulfone, or mixturesthereof; in polyphosphoric acid; with molten Lewis acids such asantimony trichloride; or with other chemical reagents, such as organictertiary amines. The method selected will depend to some extent on thespecific material being processed.

The precyclized polymers (V, VI, and VII) are prepared by processesessentially those described in US. Pat. No. 3,783,137 and in US. patentapplication Ser. No. 151,601 filed June 9, 1971. This process involvesreacting an acid salt of a triaminopyridine represented by the formulawith a substantially equimolar amount of acid derivative in a polaraprotic solvent at temperatures ranging from about 10C to about C andpreferably below about 40C to afford soluble high molecular weightprecyclized intermediates (V, VI and VII). Preferred acid salts of thetriaminopyridine are those derived from HCl, HBr, H PO CF CO l-I,alkanesulfonic, and perfluoroalkane sulfonic acids. When the acidderivative is a bis(acid halide) or mono(acid halide)anhydride, thehalogen is Cl, Br or F.

Preferred aprotic polar organic solvents are those which are at least inpart, solvents for at least one of the reactants and which, under thereaction conditions used, do not react with either of the reactants(excluding salt-formation) and which are preferably solvents for theresulting polymer. Suitable aprotic solvents in the polymerizationprocess of this invention include N,N-dimethylformamide,N,N-dimethylacetamide, N- methylpyrrolidinone, N-methylcaprolactam,hexamethylphosphoramide, tetramethylene sulfone, tetramethylurea anddimethylsulfoxide. The above solvents can be used singly, incombination, or in conjunction with aprotic solvents, such as ethers andaromatic hydrocarbons.

By using tetramethylene sulfone with or without diphenyl sulfone aspolymerization solvent, cyclized polymers can directly be prepared frommonomers. This is accomplished by careful neutralization of acid withalkali (e.g., NaOH or sodium hexafluoroisopropoxide) after formation ofprecyclized polymer, followed by gradually heating to reflux of sulfonesolvent(s), and maintaining temperature. Cyclized polymers so producedmay be isolated by washing free of salt(s) and sulfone solvent(s).

The acid derivative [bis(acid halide), mono(acid halidelanhydride, ordianhydride] is preferably added to a mixture of triamine acid salt andsolvent. More than one triamine acid salt, and more than one acidderivative may be used providing that the total moles of triamine saltare essentially equal to the total moles of acid derivative. In thismanner, interpolymers may be prepared which possess desirableproperties, such as increased solubility or processability, not shown byeither homopolymer 'alone.

The polymerization process described above can often be acceleratedduring the latter stages of polycondensation by addition of acidacceptors such as tertiary organic amines. These amines are preferablyadded after most of the acid derivative(s) have reacted, the amount ofamine being such that about l.l to 1.5 equivalents of acid per pyridinering of monomer remains unneutralized. Suitable amines for this purposeinclude triethylamine, N-methylmorpholine and diand trimethylpyridines.

Triamines which have functionally reactive groups other than amine (-NHor -NH) are preferably used in small amounts (e.g. up to 25 mole astheir acid salts to prepare copolymers or terpolymers. The presence ofsuch groups is often desirable for increasing initial polymer solubilityor for subsequent crosslinking to intractable materials. These reactivegroups include alkenyl,

C H -Cl-l=CHC l-l -CN, SH, COOH, CO,C H and -SO H. These groups areeither thermally labile to condensation reactions or addition reactionsor can be thermally condensed with amino or amido groups presentelsewhere in the polymer or present in an additive formulated with thepolymer.

Acid derivatives suitable for practicing this invention are thoserepresented by the formula:

wherein R represents a tetravalent radical possessing the structuralnuclei previously described for R R and R with the exception that when Ris carboranyl, then Z and Z: are incorporated as boron atoms of thecarborane structure (e.g. diacid chloride of 1,7- dicarbadodecaborane(l2)-l ,7-dicarboxylic acid,

and Z and Z are each selected from the group consisting of hydrogen, CHF, Cl, carbonyl and -COR where R is alkyl of 1 to 4 carbon atoms; and Qand Q are each selected from oxygen and halogen with the proviso thatwhen a Z group is hydrogen, CH halogen,

COR,,,

the corresponding Q group must be halogen, and when a 2 group iscarbonyl the corresponding 0 group must be an oxygen atom bonded to thecarbon atom of said carbonyl group; the pair of substituents and Z andthe pair of substituents providing that the CN or 0 local.

group is neither ortho or peri to a COOH group. as 2,5 inediarb xyli aid well as those diacids where one or both COOH 2 7-mhraquinonedicarboxylic acid group a fi n Oftho 1,]'-ferrocencdicarboxylic acid 0 azelaic acid flopl,S-cyclooctadiene-l,S-dicarboxylic acid l,3,5,7-cyclooctatetracnel,S-dicarboxylic acid 1 ,4cyclohcxancdicarboxylic acid group in which Ris alkyl of l to 4 carbon atoms: bip carboxyphenyl)methyl phosphineoxida g g ggfilggli c c 1 ,2.5-thiadiazolc-3,4-dicarboxylic acid2.5-dimethylterephthalic acid g zz fg fijizgggrsgg n propyl) lsophthal'cacid I 2,5-bis-(m-carboxyphenyl)-l ,3,4-0xadiazol-e 4'carb0methxy0phthahc ac'd* 3 .4-bis-(p-carboxyphenyl l ,3-40xadiazole 9 F'4,4'-sulfonyldimethylene dibenzoic acid s'suhio'sophthahc field l.7-dicarbadodecaborane( l 2)-l ,7-dicarboxylic acid 46-dlcarboethoxylsophthallc ac|d* it S-carbophenoxyisophthalic acidfumaric acid I 4.4'-stilbenedicarboxylic acid H0C C2,6-nephthalencdicarboxylic acid Y 4,8-dicarbomethoxyl,S-naphthalenedicarboxylic acid* dielhylester (nonvicinal) of3,5-dicarboxy-l,2,3,4- and those represented by the followmg formulatetrahydro-l-naphthalenesuccinic acid* 0 0 (when R, of the triamincmonomer is H) g 2,5-furandicarboxylic acid HO-CR OH2,8dibenzofurandicarboxylic acid 3,5-pyridincdicarboxylic acid in whichR represents any of the following:

-R -3-.S-X @-ElI-B-R10 x -n, on or sa l-l both X 's need not be X Xidentical.

where R equals mor p-phenylene and X is selected from zero and thedivalent radicals alkylene of l to 3 carbon atoms, (CF

where R is H, lower alkyl or phenyl; and R is methyl or phenyl; R isalkyl of l to 4 carbon atoms; r and tare integers from lto l0 and s isan integer from 2 to 10.

Suitable mono(acid halide) anhydrides and dianhydrides for practicingthis invention may be obtained from tribasic and tetrabasic acids,respectively, derived from the above dibasic acids R(OOH) by substitutedwith a COOl-l group up to two monovalent groups of R. Said -COOH groupsto be introduced will be on the B or 'y-carbons of R when R is alkyleneor cycloalkylene providing that only one COOl-l group is substi-.

tuted on a given carbon atom, or substituted on the ortho or peri carbonwhen R is arylene or heteroarylene, providing that three consecutivecarbons are not substituted with a COOH group. Representative mono(acidhalide) anhydrides and dianhydrides that have been found suitable forpracticing this invention are as follows:

trimellitic anhydride monoacid chloride 3,4,4'-benzophenonetricarboxylicanhydride monoacid chloride pyromellitic dianhydride 3 ,3.4,4'-benzophenonetetracarboxylic dianhydride pyrazinetetracarboxylicdianhydride l,4,5,8-naphthalenetetracarboxylic dianhydride bis( 3,4-dicarboxyphenoxyphenyl )sulfone dianhydride l,3bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride hexafluoropropanecyclized polymers possess enhanced solubility and hence processability.but more importantly, a lower percent of water is evolved from thepolyamide precursor during cyclodehydration. Decreased volatiles duringcyclization lead to decreased voids in the final composition whichtherefore will possess greater integrity and thermal stability.

One preferred method of tailoring polymer properties involvescopolymerization with an acid salt of an aromatic diamine or an aromatictetraamine, or mixtures thereof, in place of some of the acid salt ofthe triaminopyridine provided that the total moles of amine(s) areessentially equal to or greater than the total moles of acidreactant(s). There appears to be no limit as to the amount of triamineacid salt that can be replaced by a diamine or tetraamine acid salt, ormixtures thereof, so that the mole ratio of triamine(s) to diamine(s)and/or tetramine(s) can vary from 99/] to 1/99 or even more broadly.Furthermore, if the R group of the triamine is arylene,interpolymerization with diamines may be effected with the free basesinstead of their acid salts.

Representative diamines that are suitable for this purpose are thoserepresented by the formula in which R represents a divalent aromaticradical selected from W. M. W.

@U@. ow o.

and the ring methylated derivatives of said radicals; R is H, or CHDerivatives of the above diamines are also suitable.

For example, when the acid derivative is a bis(acid halide), diamineswhich contain a hydroxyl mercapto or SO NH group ortho to one or bothamine groups provided that no three consecutive adjacent ring positionsare substituted by amine, hydroxyl, mercapto or SO NH groups.

Preferred triaminopyridine compounds, as their acid salts. forpracticing this invention include:

2.3,5-triaminopyridine 2,3,5-triamino-4-methylpyridine2,3,5triamino-6-methylpyridine 2,3,5-triamino-4,6-dimethylpyridine3.5-diamino-Z-anilinopyridine 3,5-diamino-2-(pyridylamino)pyridine3,5-diamino-2methylaminopyridine3,5-diamino-2-anilino-4,o-dimethylpyridine Preferred triamines, as theiracid salts, containing functionally reactive groups which have beenfound to be suitable as comonomers for subsequent polymer crosslinkinginclude:

3,5diamino-2-allylaminopyridine 3.5-diamino-2-crotylaminopyridine3,5-diamino-2-stilbylaminopyridine 3,5-diamino-2-(m-R-anilino)pyridinewhere R and their ring methylated derivatives of these comonomers.-tetraaminopyridine,

Tetraamine acid salts that are suitable replacements for some of thetriaminopyridine salt in the practice of this invention are thosederived -tetraaminopyridine. 2,3,5,b-tetraaeminopyridine, 4,4',5 ,5'-tetraamino 2,2 bipyridine and those tetraamines disclosed in copendingUS. patent application Ser. No.

3,S-diamino-2,6di(methylamino)pyridine3,5-diamino-2,6-di(anilino)pyridine3,5-diamino-2,6-di(pyridylamino)pyridine and the 4methyl derivatives ofthese tetraamines.

5,5',6,6'-tetraamino-2,2-bipyridine and the N- methylated andN-phenylated amino (a or 7) derivatives of the above 2,2-bipyridines.

The cyclized polymers of this invention appear to be less vulnerable tooxidative degradation than those in which a ring CH linkage is present.Depending on the specific triamine, from zero to two such CH linkagesmay remain in the final cyclized polymer, and stability of the polymerappears to increase with decreasing CH content.

By increasing the mole ratio of triamine salt to acid derivative togreater than unity, amine-terminated adducts and uncyclized polymers oflower molecular weight may be obtained. These materials can then be 0used as reactants for the preparation of high molecular 2,3,5.6-tetraaminopyridine weight polymers which may contain monomer residuesother than the two present in the original polymerization.

The acid derivatives employed in the preparation of the polymers of thisinvention are very moisture sensitive. Reaction with water duringpolymerization will lead to partial destruction of the acid derivativewith attendant stoichiometric imbalance, lowering of molecular weight,and a decrease in thermal stability of the resulting cyclized polymer.This can be a serious problem with triamine salts that are difficult toobtain as highly pure anhydrous materials. It has been found thataddition of certain acidic inorganic oxides can scavenge moisturewithout adversely affecting the polymerization reaction. Both P 0 and B0 have been used successfully as in situ drying agents. For example, P 0in sufficient quantity upon prolonged contact with a mixture of theamine acid salt(s) and polar aprotic solvent has been used to remove atleast 10 weight water present in the salt(s). Polymer can subsequentlybe purged of P 0 or H PO by washing with water or methanol.

The following examples are illustrative of preferred embodiments of thisinvention and are not to be construed as limiting the invention in anyway.

EXAMPLE 1 Precyclized Polymer and Poly(amide-benzimidazole) from2,3,5-Triaminopyridine Trihydrochloride and 4,4-CarbonyldibenzoylChloride 4,4'-Carbonyldibenzoyl chloride,

(7.67 g, 0.025 mole), was added over five minutes under a nitrogenatmosphere to a stirred cold mixture of 2,3,5-triaminopyridinetrihydrochloride (5.84 g, 0.025 mole) and 45 g N-methylpyrrolidinone.The reaction was maintained at -5C for 2 hours and then kept at roomtemperature for four hours. The polymer solution was poured into 175 mlmethanol with stirring. The precipitate of precyclized polymer wasfiltered, washed well with methanol twice and vacuum dried overnight at50-55C. The hydrochloride polymer (9.1 g) was obtained as a yellowpowder which was soluble in N,N-dimethylformamide (DMF),dimethylsulfoxide (DMSO), and formic acid and had an inherent viscosityof 0.5 dl/g in DMF (0.5% conc., 30C). A strongly positive Beilstein testconfirmed the presence of chloride.

This polymer was neutralized as follows: the hydrochloride polymer (3.0g) was dissolved in DMF (25 m1), treated with triethylamine (1 ml) andthen precipitated into methanol and purified by filtering, washing withmethanol and vacuum drying. The neutral precyclized polymer was solublein DMF, DMSO and formic acid.

Anal. Calcd. for C, H,,N,O C, 67.0; H, 3.9; N, 15.7. Found: C, 67.2; H,4.2; N, 15.6.

Similarly other acid salts of the above precyclized polymer may beformed by replacing the trihydrochloride salt by the hydrobromide saltor the methanesulfonate salt.

The above precyclized hydrochloride polymer was converted to thecyclized polymer by heating two hours under vacuum at each of thefollowing temperatures; 150C, 200C, 300C, and 350C. The resultingpoly(amide-benzimidazole) was soluble in formic acid, CF CO H, H SO,,and methanesulfonic acid.

Anal. Calcd. for C H N O: C, 74.5; H, 3.1; N, 17.4. Found: C, 73.8; H,3.3; N, 17.2.

An amine terminated precyclized hydrochloride polymer was obtained byreaction of 4,4'-carbonyldibenzoyl chloride (0.0229 mole) with 2,3,5-triaminopyridine trihydrochloride (0.0254 mole) as described above. Thispolymer could be further extended in molecular weight by reaction in N-methylpyrrolidinone with any one of the following: 2,6-naphthalenediacid dichloride, dodecanodioic acid dichloride,3,3,4,4-benzophenonetetracarboxylie dian- Ex. Amine Acid Salt(s) 14hydride, or 2.2-bis(3',4'-dicarboxyphenyl)hexafluoropropane dianhydride.

EXAMPLE 2 Attempted Preparation of Precyclized Polymer from2,3,6-Triaminopyridine Dihydrochloride and 4,4-Carbonyldibenz0ylChloride The procedure of Example 1 was followed except that2,3,6-triaminopyridine dihydrochloride (0.025 mole) was substituted forthe 2,3,5-triaminopyridine trihydrochloride. The product isolated byprecipitation with 175 ml aqueous methanol (lv/l v) was obtained in pooryield and had an inherent viscosity of less than 0. l dl/g in DMF (0.5%conc., 30C).

EXAMPLE 3 Attempted Preparation of Precyclized Polymer from1,2,4-Triaminobenzene Dihydrochloride and 4,4'-CarbonyldibenzoylChloride The procedure of Example 1 was followed except that1,2,4-triaminobenzene dihydrochloride (0.025 mole) was .substituted forthe 2,3,5-triaminopyridine trihydrochloride. Upon addition of the last25 mole of dihydrochloride gelation resulted.

EXAMPLE 4 Precyclized Polymer and Po1y(lmidelmidazopyrrolone) from2,3,5-Triaminopyridine Trihydrochloride and3,3'4,4'-Benzophenonetetracarboxylic Dianhydride The procedure ofExample 1 was followed except that 3,3',4,4'-benzophenonetetracarboxylicdianhydride (0.025 mole) was substituted for the 4,4'-carbonyldibenzoylchloride, and the reaction was conducted 2 hours at 5-l0C and 17 hoursat room temperature. An essentially quantitative yield of precyclizedhydrochloride polymer was obtained which was soluble in DMF, DMSO, and HThe chloride-free precyclized polymer was obtained by neutralization ofthe HCl in a manner similar to that described in Example 1.

Anal. Calcd. for C H N,O-,: C, 59.2; H, 3.1; N, 12.6. Found: C, 59.0; H,3.4; N, 12.5.

The precyclized polymer above was cyclodehydrated topoly(imide-imidazopyrrolone) by heating under vacuum as described inExample 1. The cyclized polymer retained 97% of its original weightafter 100 hours exposure to air at 600F (316C).

EXAMPLES 5-18 The precyclized polymers and acid salts thereof andcyclodehydrated polymers of Examples 5-18 were prepared following theprocedures of Examples 1 and 4 except employing the indicated amine acidsalt(s) (0.100 mole) and acid derivatives (0.100 mole) and N-methylpyrrolidinone ml), unless stated otherwise.

u 1 Acid Derivative ClC-R--Cl 5. 6-methyl-TAP-3HBr /C O *3 O ContinuedII II ""DAP 3.5-diaminogyridine; TAP 2,3,5-triaminopyridine.

""Acid derivative is a is(acid chloride) unless indicated otherwise.

Hexamethylphosphoramide/F[CF(CF=,)CF CHFCF;, (iv/Iv) was substituted forthe N-methylpyrrolidinone. ""As the diacicl fluoride, r and t areintegers such that the average molecular weight is 1300.

\(g/ l.7-dicarbodecaboranyl EXAMPLES l9-24 The procedure of Example Iwas followed except that the 2,3,5-triaminopyridine. SHCI wassubstituted or partially replaced by the indicated triamine and diamineor tetraamine acid salts. in this manner the corresponding precyclizedand cyclized polymers of Examples l9-24 were obtained.

dimethylpyn'dineBHCl (50) 2,3 ,5-triamino-4-methylpyridine3HCl (50),

2 .3 ,5-triamino-2-( pmercaptoanilino)pyridine'2HCl 10)2.4-diaminobenzenesulfonamide (40) EXAMPLE 25 The effect of P 0 on thepreparation of amine terminated precyclized polymer derived from 2,3,5-triaminopyridine. 3 HCl, isophthaloyl chloride and terephthaloylchloride in the presence of water is shown by the following examples:

A mixture of isophthaloyl chloride (0.045 mole) and terephthaloylchloride (0.045 mole) was added over 30 minutes under a nitrogenatmosphere, to a well stirred mixture (0-5C) of P 0 (5.0 g), water (0.05mole). 2,3,5-triaminopyridine trihydrochloride (0. l0 mole), andN-methylpyrrolidinone (100 g). The mixture of P 0 amine salt, water, andsolvent had been previously stirred under nitrogen l0 hours at 25C. Thereaction was maintained at about 5C for 3 hours and then kept at roomtemperature for 4 hours. The polymer solution was poured into a solutionof methanol (200 ml) and water (50 ml). The precipitate of precyclizedamine terminated polymer was filtered, washed well with methanol andvacuum dried overnight at 505 5C.

B. Without P 0 The procedure of Example 25 A was followed except that noP 0 was employed. Without the P 0 the yield and molecular weight ofprecyclized polymer was considerably reduced as compared to the productobtained in Example 25 A.

I claim: 1. Precyclized polyamides consisting essentially of at leastone of the following recurring formulae:

R is a trivalent radical represented by the formula wherein one bondfrom either an a or 7 position is bonded to the NHR or NH group; and allof the R, groups are not required to be the same in the polyamide',

wherein R,,- represents a monovalent member selected from the groupconsisting of hydrogen, methyl, ethyl, propyl, butyl and pentyl, andboth R members are not required to be the same;

R: is a monovalent member selected from the group consisting ofhydrogen. alkyl, substituted alkyl, alkenyl, substituted alkenyl.arylalkyl. substituted arylalkyl, aryl. substituted aryl. heterocyclic.substituted heterocyclic. in which said substituents are selected fromthe group con sisting of methyl. phenyl. pyridyl. F(aromatic).Cllaromatic). -CN. COOH and its salts. COOC,,H,-,. SO;,H and its saltsSH. thioaryl. thioalkyl. CH=CHC.,-H,-, and N,N- (dialkylamino); and notall of the R2 groups are required to be the same in the polyamide:

R R and R are divalent, trivalent, and tetravalent radicalsrespectively, selected from the following structural types: aliphatic,cycloaliphatic, alkenyl, perfluoroalkyl, perfluoropolyalkylene oxide,aro matic and heteraromatic, and inorganic/organic radicals, thecarbocyclic and heterocyclic radicals having a single, multiple or fusedring structure, the multiple ring structures including polyarylenes with2 to 9 aryl rings in which the aryl groups are bonded directly to eachother or bridged by a divalent member selected from the group consistingof alkylene with up to 3 carbon atoms, perfluoroalkylene of 2 to 10carbon atoms,

CH=CH-, 5- and 6- membered heteroaromatics containing at least onenitrogen atom, and mixtures thereof, and substituted aromatic radicalswhere the substituents are selected from lower alkyl, F, Cl, CN, 5 SO H,and

10 with the proviso that the CN, -SO H, and

substituents are not ortho or peri to a 20 group; the inorganic/organicradicals consisting of ferrocenyl, carboranyl, and biaryls separated byat least one phosphorus atom or by at least one silanyl or siloxany]group, and mixtures thereof; R represents H, lower alkyl, or phenyl; andevery R R and R is not required to be the same as every other R R and Rand acid salts thereof, of an acid selected from the group consisting ofHCl, HBr, H PO CF COOH, alkanesulfonic and perfluoroalkane sulfonicacids.

2. Precyclized polyamides and acid salts thereof of claim 1 consistingof recurring units represented by the formula:

Eli NH3 3 wherein each R is selected from the group consisting of H,methyl, phenyl, benzyl, and pyridyl;

each R is selected from the group consisting of H and methyl and both Rs are not required to be the same;

R is a divalent radical selected from the group consisting ofm-phenylene, p-phenylene,

wherein X is selected from the group consisting of a divalent covalentbond, O. -S-,

and

o -ra and Y is selected from the group consisting of H, COOH, and--COOalk, wherein alk is lower alkyl with up to 4 carbon atoms, and bothY's are not required to be the same, with the proviso that when Y is notH, R; is H; and Z is selected from the group consisting of a divalentcovalent bond, O-, S, and

in which R is a trivalent radical represented by the formula wherein onebond from either an a or y position is bonded to the N-, Nl-lor =N groupin the above cyclized structures l-lV; and

wherein each R represents a monovalent member selected from the groupconsisting of hydrogen, methyl, ethyl, propyl, butyl and pentyl, andboth R; members are not required to be the same; and

R is a monovalent member selected from the group consisting of hydrogen,alkyl, substituted alkyl, alkenyl, substituted alkenyl, arylalkyl,substituted arylalkyl, aryl, substituted aryl, heterocyclic, substitutedheterocyclic; said substituents being selected from the group consistingof methyl, phenyl, pyridyl, F(aromatic), Cl(aromatic), CN, COOH and itssalts, COOC H SO H and its salts, -SH, thioaryl, thioalkyl, CH=CHC,H,,.and N,N-(dialkylamino), with the proviso that each of the several R 's,R2S, R s, R s and R s in any 22 recurring unit is not required to be thesame as the R's in any other recurring unit, and the symbol representspossible isomerism. 4. The precyclized polyamides and acid salts thereof5 of claim 1 wherein at least a portion of the radical is replaced by adivalent aromatic radical.

5. The polymers of claim 4 after cyclodehydration. 6. The precyclizedpolyamides of claim 1 wherein at least a portion of the radical isreplaced by a divalent pyridyl or polypyridyl radical represented by oneof the following formulae:

RN:@ R)

with a substantially equimolar amount of at least one acid derivative ina polar aprotic solvent at temperatures ranging from about l0C to aboutC and in the presence of P 0 wherein the acid derivative is selectedfrom the group consisting of bis(acid halides),

23 24 H2N HQN NR2 HZN NH2 I21 H ll NH? N N N (X or 3) (A or 2')mono(acid halide) anhydrides, and dianhydrides; wherein R and R are asdefined in claim 1. fi 2 and s are as defined in Claim 1, and the 10.The polymers of claim 3 in which at least some acid in said acidderivative is selected from the group f th R g u are selected from thegroup consisting consisting of HCl, HBr. H PO CF COOH. alkanesulf any],crow], C6H5CH=CH C6H4 and fonic and perfluoroalkanesulfonic acids.

9. The process of claim 8 wherein the pyridyl acid i it salt ispartially replaced by at least one acid salt of an aromatic diamine oran aromatic amine represented by the formulae:

1. PRECYCLIZED POLYAMIDES CONSISTING ESSENTIALLY OF AT LEAST ONE OF THEFOLLOWING RECURRING FORMULAE:
 2. Precyclized polyamides and acid saltsthereof of claim 1 consisting of recurring units represented by theformula:
 3. CYCLIZED HETEROCYCLIC POLYMERS PREPARED BY CYCLODEHYDRATIONOF THE POLYAMIDES AND ACID SALTS THEREOF OF CLAIM 1 AND WHICH CONTAINRECURRING STRUCTURAL UNITS CONSISTING ESSENTIALLY OF AT LEAST ONE OF THEFOLLOWING FORMULAE:
 4. The precyclized polyamides and acid salts thereofof claim 1 wherein at least a portion of the radical
 5. The polymers ofclaim 4 after cyclodehydration.
 6. The precyclized polyamides of claim 1wherein at least a portion of the radical
 7. The polymers of claim 6after cyclodehyDration.
 8. A process for producing the precyclizedpolyamides of claim 1 which comprises reacting at least one acid salt ofa triminopyridine represented by the formula
 9. The process of claim 8wherein the pyridyl acid salt is partially replaced by at least one acidsalt of an aromatic diamine or an aromatic amine represented by theformulae:
 10. The polymers of claim 3 in which at least some of the R2groups are selected from the group consisting of allyl, crotyl, C6H5CHCH-C6H4-, and